tools lib fd array: Allow associating an integer cookie with each entry
We will use this in perf's evlist class so that it can, at
fdarray__filter() time, to unmap the associated ring buffer.
We may need to have further info associated with each fdarray entry, in
that case we'll make that int array a 'union fdarray_priv' one and put a
pointer there so that users can stash whatever they want there. For now,
an int is enough tho.
v2: Add clarification to the per array entry priv area, as well as make
it a union, which makes usage a bit longer, but if/when we make it
use more space by allowing per entry pointers existing users source
code will not have to be changed, just rebuilt.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: http://lkml.kernel.org/n/tip-0p00bn83quck3fio3kcs9vca@git.kernel.org
diff --git a/tools/lib/api/fd/array.c b/tools/lib/api/fd/array.c
index 4889c7d..0e636c4 100644
--- a/tools/lib/api/fd/array.c
+++ b/tools/lib/api/fd/array.c
@@ -13,21 +13,31 @@
void fdarray__init(struct fdarray *fda, int nr_autogrow)
{
fda->entries = NULL;
+ fda->priv = NULL;
fda->nr = fda->nr_alloc = 0;
fda->nr_autogrow = nr_autogrow;
}
int fdarray__grow(struct fdarray *fda, int nr)
{
+ void *priv;
int nr_alloc = fda->nr_alloc + nr;
+ size_t psize = sizeof(fda->priv[0]) * nr_alloc;
size_t size = sizeof(struct pollfd) * nr_alloc;
struct pollfd *entries = realloc(fda->entries, size);
if (entries == NULL)
return -ENOMEM;
+ priv = realloc(fda->priv, psize);
+ if (priv == NULL) {
+ free(entries);
+ return -ENOMEM;
+ }
+
fda->nr_alloc = nr_alloc;
fda->entries = entries;
+ fda->priv = priv;
return 0;
}
@@ -50,6 +60,7 @@
void fdarray__exit(struct fdarray *fda)
{
free(fda->entries);
+ free(fda->priv);
fdarray__init(fda, 0);
}
@@ -61,6 +72,8 @@
int fdarray__add(struct fdarray *fda, int fd, short revents)
{
+ int pos = fda->nr;
+
if (fda->nr == fda->nr_alloc &&
fdarray__grow(fda, fda->nr_autogrow) < 0)
return -ENOMEM;
@@ -68,10 +81,11 @@
fda->entries[fda->nr].fd = fd;
fda->entries[fda->nr].events = revents;
fda->nr++;
- return 0;
+ return pos;
}
-int fdarray__filter(struct fdarray *fda, short revents)
+int fdarray__filter(struct fdarray *fda, short revents,
+ void (*entry_destructor)(struct fdarray *fda, int fd))
{
int fd, nr = 0;
@@ -79,11 +93,17 @@
return 0;
for (fd = 0; fd < fda->nr; ++fd) {
- if (fda->entries[fd].revents & revents)
- continue;
+ if (fda->entries[fd].revents & revents) {
+ if (entry_destructor)
+ entry_destructor(fda, fd);
- if (fd != nr)
+ continue;
+ }
+
+ if (fd != nr) {
fda->entries[nr] = fda->entries[fd];
+ fda->priv[nr] = fda->priv[fd];
+ }
++nr;
}